I B.Tech - Regular Examinations, June 2009
First Year
ELECTRONIC DEVICES AND CIRCUITS- SET NO: 3
(Regulation 2007)
Time : 3 hours |
Maximam Marks:80 |
Answer any FIVE Questions
1. Two plane parallel plates A and B are placed 3 mm apart and potential of b is
made 200 V positive with respect to plate A. An electron starts from rest from
plate A. Calculate
(a) The velocity of the electron on reaching plate B.
(b) Time taken by the electron to travel from plate A to plate B, and
(c) Kinetic energy of the electron on reaching the plate B.
2. (a) Explain about semiconductor, Insulator & Conductor with neat sketch.
(b) State the Einstein relationship for semiconductor.
(c) State paulis exclusion principle.
3.Derive the ripple factor of capacitor filter.
4.Derive the analytical expression for transistgor characteristics.
5.In a germanium transistor CE amplifier biased by feedback resistor method , VCC
= 20 V, VBE = 0.2 V, ß = 100 and the operating point is chosen such that VCE =
10.4 V and IC = 9.9mA, determine the value of RB and RC.
6.A transistor used in a CC Circuit as shown in Figure 6. has the following set of h
parameters.
hic = 2 K
, hfc = -51, hrc = 1, hoc = 25 × 10-6
Find the values of input and output resistances, current and voltage gains of the
amplifier stage. Use the approximate analysis.
7.(a) How the distortion is decreased in negative feedback?
(b) An amplifier has an open loop gain of 1000 and a feedback ration of 0.04. if
the open loop gain changes by 10% due to temperature, find the percentage
change in gain of he amplifier with feed back.
8.The frequency of oscillation of a colpitts oscillator is given by,
This circuit operates at 450 KHz with C1 = C2 what will be the oscillation frequency
if the value of C2 is doubled?
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